About Holothuria difficilis Semper, 1868
Holothuria difficilis Semper, 1868 is a member of the phylum Echinodermata, and shares the general body plan of other members of this phylum. These shared traits include pentamerous radial symmetry, an endoskeleton, an oral side opposite the aboral side, a water vascular system, and tube feet. The oral side holds the mouth for feeding, while the aboral side holds an anus that is used both to expel waste and for respiration. Tube feet are used for locomotion. H. difficilis also has several defense mechanisms. Structurally, its dermis is noxious, and it also has very thin Cuvierian tubules that can be ejected. It has been hypothesized that these defense mechanisms, found in animals such as holothurians, evolved as protection against predation. This species has a single gonad and can carry out sexual reproduction. The species has been found in many seas and oceans across the globe, including the Red Sea and waters near Central America, though its general distribution is within the Indian and Pacific Oceans. This species is typically benthic and lives inshore. When observed in fringing reefs of La Reunion Island, the species lived on outer reef flats and under large boulders.
